This is a study of the impact of state certificate of need regulation on hospitals in the United States. It is designed to produce both policy relevant and significant political science discipline results. The policy section will first determine the effect of certificate of need regulation on costs, utilization, and facilities. The effectiveness of different state programs will then be compared. Finally, the key manipulated policy variables associated with effectiveness will be identified. The object of this section is to produce findings that will be of direct relevance to legislators and other policy makers in choosing approaches that will effectively implement certificate of need programs. The research should also produce important findings for political science theories. The study will formulate specific propositions from the literature on regulation and then test them using the data on hospital facilities. The explicit test of theories of regulation should not only advance political science but should also be useful for regulatory programs in other policy areas. The study will use multiple regression analysis to estimate the impact of certificate of need programs. The data allow both cross sectional and time series analysis. Thus states with certificate of need programs (24 in 1972) can be compared to states that have no such regulation, and a single state can be examined for any changes in trends after the operation of controls. The data set contains values from 51 states from 1960 to 1975 on such variables as hospital beds, assets, vendor payments, doctors, etc.